Automatic cut-off for gas-mains.



c. E. LAHMBRSL AUTOMATIC GUT-OFF FDR GAS MAINS.

APPLICATION FILED APR. 26,1909.

Patented Jan. 11,1910.

WITNESSES INVEIVTUR M CHARLEs ELAHMERS ATTORNEY UITED STATES PET EFIQE.

CHARLES E. LAI-IMERS, OF NEW PHILADELPHIA, OHIO.

AUTOMATIC CUT-OFF FOR GAS-MAINS.

T 0 all whom it may concern:

Be it known that I, CHARLES E. LAHMERs, a citizen of the United States,and a resident of New Philadelphia, in the county of Tuscarawas andState of Ohio, have made certain new and useful Improvements inAutomaticCut-Ofi for Gas-Mains, of which the following is aspecification.

My invention relates to devices for preventing explosions or accidentscaused by changes in the pressure in gas mains, and it consists in theconstructions, combinations and arrangements herein described andclaimed. I

The invention is similar to one disclosed in my copending applicationSerial No. 482,299, filed March 9, 1909, the present applicationrelating more particularly to the specific valve mechanism.

It often happens that the pressure on the mains of a city gas systembecomes so low that at times the flow of gas from the jets communicatingtherewith is stopped altogether. This is especially true of the burnersof gas stoves and the like, which, when left burning, will frequently goout at certain periods of the day when the pressure is low. If the cooksare not turned OK,

,.the gas begins to flow when the pressure comes on again and there isdanger of an explosion when the gas is again lighted or the freelyflowing gas itself is liable to fill the house or apartment with itspoisonous fumes.

An object of my invention is to provide a device which willautomatically shut off the flow of gas from the mains when the pressuretherein becomes too low, thereby preventing the accidents which mightotherwise occur.

A further object of iny invention is to provide a device of few partsand of comparatively little cost for accomplishing the above results.

A further object of my invention is to provide an automatic cut 05,whose working parts are entirely of metal, which will resist wear andlast considerably longer than devices depending for their operation uponparts made of resilient material such as rubber or the like.

Further objects and advantages will appear in the followingspecification and the novel features of the invention will beparticularly pointed out in the appended claims.

Specification of Letters Patent.

Application filed. April 26, 1909.

Patented Jan. 11, 1910. Serial No. 492,274.

My invention is illustrated in the accompanying drawings in which Figure1 is a central Vertical section through the device showing it in anopened position, and Fig. 2 is a similar view showing the device in aclosed position.

In carrying out my invention I provide a main casing consisting of anupper portion A and a lower portion B. The upper portion A is preferablya hollow cylinder and has a smaller cylinder C disposed within the outercylinder but being joined to it at the bottom. This constructionprovides an annular space D between the two cylinders as clearly shownin the two drawings. The top of the cylinder B is closed by a screwthreaded cap E, having a recess 6, and provided with lugs 6 K is ahandle which has a stem that extends downwardly through the cap and isprovided on its lower end with a threaded member 70 The lower portion Bof the casing is providecl with an inlet pipe G and the outlet pipe H. Astationary tube M is threaded at m to engage corresponding threads onboth portions of the casing A and B so that the latter are heldtogether. The cylinder H is provided with two openings 9 and h. Thelower end of the casing B is closed by a screw threaded cap L.

Vithin the cylinder M is disposed a slidable cylinder T which fits closeto the interior walls of the cylinder M. The cylinder T is provided atits upper end with an integral head t which joins the cylinder T with anouter concentric cylinder V which is disposed between the outer casing Aand the cylinder C in the annular space D. The head 2 is provided with athreaded recess 6 into which the end 76 of the stem is is arranged toenter. It is also provided with recesses t into which the lugs c on thecap E may enter.

A packing gland F is provided for preventing the escape of gas into thebuilding, in the event that the gas should get above the cylinder V.Ordinarily the screw member of the packing gland is left loose but incases where the device is left in connection with the mains and is notintended to be used the gland may be screwed down tight on the rod 6 soas .to absolutely prevent any danger of leakage of the gas into thebuilding.

From the foregoing description of the various parts of the device, theoperation thereof may be readily understood. The cut-off may be locatedat any convenient place but is preferably placed in a building betweenthe meter and the distributing pipes. The device is normally arranged asshown in Fig. 1. Before the device is assembled, a quantity of mercury Pis poured into the annular space D. The amount of mercury used will varywith different sized cut-offs. The buoyant force of the mercury togetherwith the gas pressure will keep the cylinder T in its upper positionshown in Fig. 1. The gas enters the inlet 9 from the pipe G and passesupward through the interior of the cylinder T and thence through theopenings t into the space between the surface of the mercury and theunderside of the heat 6. This pressure as stated before is sufficient tokeep the cylinder T suspended. Now when the pressure becomes low theweight of the cylinder T, the head 6 and the cylinder V causes theseparts to descend, the cylinder V passing down into the mercury andtaking the position shown in Fig. 2. The lower end of the cylinder T hasnow shut off the inlet and the outlet openings 9 and 71, whereupon theflow of gas is stopped. lVhen it is desired to start the flow againafter the pressure comes on, the handle K is depressed, until the headif enters the recess F. A few turns of the handle secures the latter tothe head t which together with the cylinders T and V may be drawn upinto the position shown in Fig. 1, the pressure being on these partswill be kept suspended. The handle may then be unscrewed from the top T(the lugs t preventing the head from turning) and the device will beset, ready for cutting off the flow again should the pressure decrease.

I am aware that other forms of the device 5 based upon the same generalprinciple might be made but I consider as my own all such modificationsas fairly fall within the spirit and the scope of my invention.

I claim:

1. An automatic cut off comprising a casing provided with a chamber andopenings for the admission and exit of gas, a liquid disposed in saidchamber, a movable member having a portion adapted to be submerged in aportion of said liquid and having a downwardly extending central portionarranged to open and close said openings, and means for admitting thegas through said openings on the underside of said movable memberthereby causing said member to remain suspended when the gas pressure ison and to descend and close such openings when the gas pressure isdecreased.

2. An automatic cut off comprising a hollow casing having an annularchamber partly filled with mercury, a stationary cylinder disposedwithin said annular chamber and provided with openings for the admissionand exit of gas, a central cylinder disposed within said stationarycylinder and adapted to open and close said openings, said cylinderbeing connected with a second concentric cylinder disposed in saidannular chamber and subjected to the buoyant force of the mercury, saidcentral cylinder being provided with openings at its upper end for theadmission of gas into said annular chamber.

3. An automatic cut-off comprising a hollow casing provided withinwardly projecting lugs and having an annular chamber therein partlyfilled with mercury, a stationary tube disposed centrally of said casingand provided with openings, outlet and inlet openings near its lower endarranged to register with the openings in the stationary tube, a movablevalve member comprising a cylinder closed at one end and provided withopenings arranged to receive the lugs of said casing, the lower part ofthe cylinder being submerged in the mercury, and a centrally dependingtube integral with said cylinder, disposed within said stationary tubeand provided with openings at its upper end and arranged to close theopenings in said stationary tube at the downward movement, and meansprojecting through said casing for engaging said mov able valve memberfor resetting it.

CHARLES E. LAHMERS.

lVitnesses TV. I. Kinsey, JOHN 0. Joss.

